1. Field of the Invention
The present invention relates to a method and apparatus for electrically connecting a plurality of flexible film wiring boards juxtaposed together to a common wiring board. The present invention also relates to an ink jet recording head having a wiring structure realized by the connecting method and apparatus and to an ink jet recording apparatus using such an ink jet recording head.
2. Related Background Art
Ink jet recording apparatuses are recording apparatuses of a so-called non-impact type. A recording apparatus of this type is characterized in that it can record at high speed, can use a variety type of recording media, and hardly generates noises during recording. From this reason, it has been widely used by apparatuses having a recording mechanism such as printers, word processors, facsimiles and photocopiers.
For ink jet recording, a fine droplet is jetted out from a minute jet port onto a recording sheet. As a typical one, a method using electrothermal conversion elements is known. For such ink jet recording, generally an ink jet recording head and an ink supply system are used, the former having nozzles for forming droplets and the latter supplying ink to the head. In an ink jet recording head using electrothermal conversion elements, each electrothermal conversion element mounted on a nozzle is supplied with an electric pulse as a recording signal to conduct thermal energy to recording liquid. A bubble pressure caused by phase transition of the recording liquid to a bubbling (boiling) state is utilized to jet out a recording droplet.
The type of an ink jet recording head using electrothermal conversion heads includes a type (called an "edge shooter type") which jets out recording liquid in parallel to a substrate on which electrothermal conversion elements are mounted and another type (called a "side shooter type") which jets out recording liquid perpendicular to a substrate on which electrothermal conversion elements are mounted.
In order to supply such an ink jet recording head with an electric pulse as a recording signal, wiring boards have been used. Terminals on a plurality of wiring boards are electrically interconnected in some cases from the reason of manufacture or the like. In such cases, if terminals are not interconnected reliably between wiring boards, electrical conduction defects may occur. However, if the total manufacture efficiency of ink jet recording apparatuses becomes low or the size thereof becomes large in order to ensure the reliability of electrical conduction, this is meaningless in terms of practical use.
Such a technical issue becomes more strict as the number of jet ports of an ink jet recording head increases and the number of signal lines via which an electric pulse is applied to the head increases.